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x86: merge process.c a bit
[linux-2.6.git] / crypto / api.c
blob314dab96840e2792ee7af4b205b2ab63722faac4
1 /*
2 * Scatterlist Cryptographic API.
3 *
4 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
5 * Copyright (c) 2002 David S. Miller (davem@redhat.com)
6 * Copyright (c) 2005 Herbert Xu <herbert@gondor.apana.org.au>
7 *
8 * Portions derived from Cryptoapi, by Alexander Kjeldaas <astor@fast.no>
9 * and Nettle, by Niels Möller.
10 *
11 * This program is free software; you can redistribute it and/or modify it
12 * under the terms of the GNU General Public License as published by the Free
13 * Software Foundation; either version 2 of the License, or (at your option)
14 * any later version.
15 *
16 */
17
18 #include <linux/err.h>
19 #include <linux/errno.h>
20 #include <linux/kernel.h>
21 #include <linux/kmod.h>
22 #include <linux/module.h>
23 #include <linux/param.h>
24 #include <linux/sched.h>
25 #include <linux/slab.h>
26 #include <linux/string.h>
27 #include "internal.h"
28
29 LIST_HEAD(crypto_alg_list);
30 EXPORT_SYMBOL_GPL(crypto_alg_list);
31 DECLARE_RWSEM(crypto_alg_sem);
32 EXPORT_SYMBOL_GPL(crypto_alg_sem);
33
34 BLOCKING_NOTIFIER_HEAD(crypto_chain);
35 EXPORT_SYMBOL_GPL(crypto_chain);
36
37 static inline struct crypto_alg *crypto_alg_get(struct crypto_alg *alg)
38 {
39 atomic_inc(&alg->cra_refcnt);
40 return alg;
41 }
42
43 struct crypto_alg *crypto_mod_get(struct crypto_alg *alg)
44 {
45 return try_module_get(alg->cra_module) ? crypto_alg_get(alg) : NULL;
46 }
47 EXPORT_SYMBOL_GPL(crypto_mod_get);
48
49 void crypto_mod_put(struct crypto_alg *alg)
50 {
51 struct module *module = alg->cra_module;
52
53 crypto_alg_put(alg);
54 module_put(module);
55 }
56 EXPORT_SYMBOL_GPL(crypto_mod_put);
57
58 static inline int crypto_is_test_larval(struct crypto_larval *larval)
59 {
60 return larval->alg.cra_driver_name[0];
61 }
62
63 static struct crypto_alg *__crypto_alg_lookup(const char *name, u32 type,
64 u32 mask)
65 {
66 struct crypto_alg *q, *alg = NULL;
67 int best = -2;
68
69 list_for_each_entry(q, &crypto_alg_list, cra_list) {
70 int exact, fuzzy;
71
72 if (crypto_is_moribund(q))
73 continue;
74
75 if ((q->cra_flags ^ type) & mask)
76 continue;
77
78 if (crypto_is_larval(q) &&
79 !crypto_is_test_larval((struct crypto_larval *)q) &&
80 ((struct crypto_larval *)q)->mask != mask)
81 continue;
82
83 exact = !strcmp(q->cra_driver_name, name);
84 fuzzy = !strcmp(q->cra_name, name);
85 if (!exact && !(fuzzy && q->cra_priority > best))
86 continue;
87
88 if (unlikely(!crypto_mod_get(q)))
89 continue;
90
91 best = q->cra_priority;
92 if (alg)
93 crypto_mod_put(alg);
94 alg = q;
95
96 if (exact)
97 break;
98 }
99
100 return alg;
101 }
102
103 static void crypto_larval_destroy(struct crypto_alg *alg)
104 {
105 struct crypto_larval *larval = (void *)alg;
106
107 BUG_ON(!crypto_is_larval(alg));
108 if (larval->adult)
109 crypto_mod_put(larval->adult);
110 kfree(larval);
111 }
112
113 struct crypto_larval *crypto_larval_alloc(const char *name, u32 type, u32 mask)
114 {
115 struct crypto_larval *larval;
116
117 larval = kzalloc(sizeof(*larval), GFP_KERNEL);
118 if (!larval)
119 return ERR_PTR(-ENOMEM);
120
121 larval->mask = mask;
122 larval->alg.cra_flags = CRYPTO_ALG_LARVAL | type;
123 larval->alg.cra_priority = -1;
124 larval->alg.cra_destroy = crypto_larval_destroy;
125
126 strlcpy(larval->alg.cra_name, name, CRYPTO_MAX_ALG_NAME);
127 init_completion(&larval->completion);
128
129 return larval;
130 }
131 EXPORT_SYMBOL_GPL(crypto_larval_alloc);
132
133 static struct crypto_alg *crypto_larval_add(const char *name, u32 type,
134 u32 mask)
135 {
136 struct crypto_alg *alg;
137 struct crypto_larval *larval;
138
139 larval = crypto_larval_alloc(name, type, mask);
140 if (IS_ERR(larval))
141 return ERR_CAST(larval);
142
143 atomic_set(&larval->alg.cra_refcnt, 2);
144
145 down_write(&crypto_alg_sem);
146 alg = __crypto_alg_lookup(name, type, mask);
147 if (!alg) {
148 alg = &larval->alg;
149 list_add(&alg->cra_list, &crypto_alg_list);
150 }
151 up_write(&crypto_alg_sem);
152
153 if (alg != &larval->alg)
154 kfree(larval);
155
156 return alg;
157 }
158
159 void crypto_larval_kill(struct crypto_alg *alg)
160 {
161 struct crypto_larval *larval = (void *)alg;
162
163 down_write(&crypto_alg_sem);
164 list_del(&alg->cra_list);
165 up_write(&crypto_alg_sem);
166 complete_all(&larval->completion);
167 crypto_alg_put(alg);
168 }
169 EXPORT_SYMBOL_GPL(crypto_larval_kill);
170
171 static struct crypto_alg *crypto_larval_wait(struct crypto_alg *alg)
172 {
173 struct crypto_larval *larval = (void *)alg;
174 long timeout;
175
176 timeout = wait_for_completion_interruptible_timeout(
177 &larval->completion, 60 * HZ);
178
179 alg = larval->adult;
180 if (timeout < 0)
181 alg = ERR_PTR(-EINTR);
182 else if (!timeout)
183 alg = ERR_PTR(-ETIMEDOUT);
184 else if (!alg)
185 alg = ERR_PTR(-ENOENT);
186 else if (crypto_is_test_larval(larval) &&
187 !(alg->cra_flags & CRYPTO_ALG_TESTED))
188 alg = ERR_PTR(-EAGAIN);
189 else if (!crypto_mod_get(alg))
190 alg = ERR_PTR(-EAGAIN);
191 crypto_mod_put(&larval->alg);
192
193 return alg;
194 }
195
196 struct crypto_alg *crypto_alg_lookup(const char *name, u32 type, u32 mask)
197 {
198 struct crypto_alg *alg;
199
200 down_read(&crypto_alg_sem);
201 alg = __crypto_alg_lookup(name, type, mask);
202 up_read(&crypto_alg_sem);
203
204 return alg;
205 }
206 EXPORT_SYMBOL_GPL(crypto_alg_lookup);
207
208 struct crypto_alg *crypto_larval_lookup(const char *name, u32 type, u32 mask)
209 {
210 struct crypto_alg *alg;
211
212 if (!name)
213 return ERR_PTR(-ENOENT);
214
215 mask &= ~(CRYPTO_ALG_LARVAL | CRYPTO_ALG_DEAD);
216 type &= mask;
217
218 alg = crypto_alg_lookup(name, type, mask);
219 if (!alg) {
220 char tmp[CRYPTO_MAX_ALG_NAME];
221
222 request_module(name);
223
224 if (!((type ^ CRYPTO_ALG_NEED_FALLBACK) & mask) &&
225 snprintf(tmp, sizeof(tmp), "%s-all", name) < sizeof(tmp))
226 request_module(tmp);
227
228 alg = crypto_alg_lookup(name, type, mask);
229 }
230
231 if (alg)
232 return crypto_is_larval(alg) ? crypto_larval_wait(alg) : alg;
233
234 return crypto_larval_add(name, type, mask);
235 }
236 EXPORT_SYMBOL_GPL(crypto_larval_lookup);
237
238 int crypto_probing_notify(unsigned long val, void *v)
239 {
240 int ok;
241
242 ok = blocking_notifier_call_chain(&crypto_chain, val, v);
243 if (ok == NOTIFY_DONE) {
244 request_module("cryptomgr");
245 ok = blocking_notifier_call_chain(&crypto_chain, val, v);
246 }
247
248 return ok;
249 }
250 EXPORT_SYMBOL_GPL(crypto_probing_notify);
251
252 struct crypto_alg *crypto_alg_mod_lookup(const char *name, u32 type, u32 mask)
253 {
254 struct crypto_alg *alg;
255 struct crypto_alg *larval;
256 int ok;
257
258 if (!((type | mask) & CRYPTO_ALG_TESTED)) {
259 type |= CRYPTO_ALG_TESTED;
260 mask |= CRYPTO_ALG_TESTED;
261 }
262
263 larval = crypto_larval_lookup(name, type, mask);
264 if (IS_ERR(larval) || !crypto_is_larval(larval))
265 return larval;
266
267 ok = crypto_probing_notify(CRYPTO_MSG_ALG_REQUEST, larval);
268
269 if (ok == NOTIFY_STOP)
270 alg = crypto_larval_wait(larval);
271 else {
272 crypto_mod_put(larval);
273 alg = ERR_PTR(-ENOENT);
274 }
275 crypto_larval_kill(larval);
276 return alg;
277 }
278 EXPORT_SYMBOL_GPL(crypto_alg_mod_lookup);
279
280 static int crypto_init_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
281 {
282 const struct crypto_type *type_obj = tfm->__crt_alg->cra_type;
283
284 if (type_obj)
285 return type_obj->init(tfm, type, mask);
286
287 switch (crypto_tfm_alg_type(tfm)) {
288 case CRYPTO_ALG_TYPE_CIPHER:
289 return crypto_init_cipher_ops(tfm);
290
291 case CRYPTO_ALG_TYPE_DIGEST:
292 if ((mask & CRYPTO_ALG_TYPE_HASH_MASK) !=
293 CRYPTO_ALG_TYPE_HASH_MASK)
294 return crypto_init_digest_ops_async(tfm);
295 else
296 return crypto_init_digest_ops(tfm);
297
298 case CRYPTO_ALG_TYPE_COMPRESS:
299 return crypto_init_compress_ops(tfm);
300
301 default:
302 break;
303 }
304
305 BUG();
306 return -EINVAL;
307 }
308
309 static void crypto_exit_ops(struct crypto_tfm *tfm)
310 {
311 const struct crypto_type *type = tfm->__crt_alg->cra_type;
312
313 if (type) {
314 if (tfm->exit)
315 tfm->exit(tfm);
316 return;
317 }
318
319 switch (crypto_tfm_alg_type(tfm)) {
320 case CRYPTO_ALG_TYPE_CIPHER:
321 crypto_exit_cipher_ops(tfm);
322 break;
323
324 case CRYPTO_ALG_TYPE_DIGEST:
325 crypto_exit_digest_ops(tfm);
326 break;
327
328 case CRYPTO_ALG_TYPE_COMPRESS:
329 crypto_exit_compress_ops(tfm);
330 break;
331
332 default:
333 BUG();
334
335 }
336 }
337
338 static unsigned int crypto_ctxsize(struct crypto_alg *alg, u32 type, u32 mask)
339 {
340 const struct crypto_type *type_obj = alg->cra_type;
341 unsigned int len;
342
343 len = alg->cra_alignmask & ~(crypto_tfm_ctx_alignment() - 1);
344 if (type_obj)
345 return len + type_obj->ctxsize(alg, type, mask);
346
347 switch (alg->cra_flags & CRYPTO_ALG_TYPE_MASK) {
348 default:
349 BUG();
350
351 case CRYPTO_ALG_TYPE_CIPHER:
352 len += crypto_cipher_ctxsize(alg);
353 break;
354
355 case CRYPTO_ALG_TYPE_DIGEST:
356 len += crypto_digest_ctxsize(alg);
357 break;
358
359 case CRYPTO_ALG_TYPE_COMPRESS:
360 len += crypto_compress_ctxsize(alg);
361 break;
362 }
363
364 return len;
365 }
366
367 void crypto_shoot_alg(struct crypto_alg *alg)
368 {
369 down_write(&crypto_alg_sem);
370 alg->cra_flags |= CRYPTO_ALG_DYING;
371 up_write(&crypto_alg_sem);
372 }
373 EXPORT_SYMBOL_GPL(crypto_shoot_alg);
374
375 struct crypto_tfm *__crypto_alloc_tfm(struct crypto_alg *alg, u32 type,
376 u32 mask)
377 {
378 struct crypto_tfm *tfm = NULL;
379 unsigned int tfm_size;
380 int err = -ENOMEM;
381
382 tfm_size = sizeof(*tfm) + crypto_ctxsize(alg, type, mask);
383 tfm = kzalloc(tfm_size, GFP_KERNEL);
384 if (tfm == NULL)
385 goto out_err;
386
387 tfm->__crt_alg = alg;
388
389 err = crypto_init_ops(tfm, type, mask);
390 if (err)
391 goto out_free_tfm;
392
393 if (!tfm->exit && alg->cra_init && (err = alg->cra_init(tfm)))
394 goto cra_init_failed;
395
396 goto out;
397
398 cra_init_failed:
399 crypto_exit_ops(tfm);
400 out_free_tfm:
401 if (err == -EAGAIN)
402 crypto_shoot_alg(alg);
403 kfree(tfm);
404 out_err:
405 tfm = ERR_PTR(err);
406 out:
407 return tfm;
408 }
409 EXPORT_SYMBOL_GPL(__crypto_alloc_tfm);
410
411 /*
412 * crypto_alloc_base - Locate algorithm and allocate transform
413 * @alg_name: Name of algorithm
414 * @type: Type of algorithm
415 * @mask: Mask for type comparison
416 *
417 * This function should not be used by new algorithm types.
418 * Plesae use crypto_alloc_tfm instead.
419 *
420 * crypto_alloc_base() will first attempt to locate an already loaded
421 * algorithm. If that fails and the kernel supports dynamically loadable
422 * modules, it will then attempt to load a module of the same name or
423 * alias. If that fails it will send a query to any loaded crypto manager
424 * to construct an algorithm on the fly. A refcount is grabbed on the
425 * algorithm which is then associated with the new transform.
426 *
427 * The returned transform is of a non-determinate type. Most people
428 * should use one of the more specific allocation functions such as
429 * crypto_alloc_blkcipher.
430 *
431 * In case of error the return value is an error pointer.
432 */
433 struct crypto_tfm *crypto_alloc_base(const char *alg_name, u32 type, u32 mask)
434 {
435 struct crypto_tfm *tfm;
436 int err;
437
438 for (;;) {
439 struct crypto_alg *alg;
440
441 alg = crypto_alg_mod_lookup(alg_name, type, mask);
442 if (IS_ERR(alg)) {
443 err = PTR_ERR(alg);
444 goto err;
445 }
446
447 tfm = __crypto_alloc_tfm(alg, type, mask);
448 if (!IS_ERR(tfm))
449 return tfm;
450
451 crypto_mod_put(alg);
452 err = PTR_ERR(tfm);
453
454 err:
455 if (err != -EAGAIN)
456 break;
457 if (signal_pending(current)) {
458 err = -EINTR;
459 break;
460 }
461 }
462
463 return ERR_PTR(err);
464 }
465 EXPORT_SYMBOL_GPL(crypto_alloc_base);
466
467 void *crypto_create_tfm(struct crypto_alg *alg,
468 const struct crypto_type *frontend)
469 {
470 char *mem;
471 struct crypto_tfm *tfm = NULL;
472 unsigned int tfmsize;
473 unsigned int total;
474 int err = -ENOMEM;
475
476 tfmsize = frontend->tfmsize;
477 total = tfmsize + sizeof(*tfm) + frontend->extsize(alg, frontend);
478
479 mem = kzalloc(total, GFP_KERNEL);
480 if (mem == NULL)
481 goto out_err;
482
483 tfm = (struct crypto_tfm *)(mem + tfmsize);
484 tfm->__crt_alg = alg;
485
486 err = frontend->init_tfm(tfm, frontend);
487 if (err)
488 goto out_free_tfm;
489
490 if (!tfm->exit && alg->cra_init && (err = alg->cra_init(tfm)))
491 goto cra_init_failed;
492
493 goto out;
494
495 cra_init_failed:
496 crypto_exit_ops(tfm);
497 out_free_tfm:
498 if (err == -EAGAIN)
499 crypto_shoot_alg(alg);
500 kfree(mem);
501 out_err:
502 mem = ERR_PTR(err);
503 out:
504 return mem;
505 }
506 EXPORT_SYMBOL_GPL(crypto_create_tfm);
507
508 /*
509 * crypto_alloc_tfm - Locate algorithm and allocate transform
510 * @alg_name: Name of algorithm
511 * @frontend: Frontend algorithm type
512 * @type: Type of algorithm
513 * @mask: Mask for type comparison
514 *
515 * crypto_alloc_tfm() will first attempt to locate an already loaded
516 * algorithm. If that fails and the kernel supports dynamically loadable
517 * modules, it will then attempt to load a module of the same name or
518 * alias. If that fails it will send a query to any loaded crypto manager
519 * to construct an algorithm on the fly. A refcount is grabbed on the
520 * algorithm which is then associated with the new transform.
521 *
522 * The returned transform is of a non-determinate type. Most people
523 * should use one of the more specific allocation functions such as
524 * crypto_alloc_blkcipher.
525 *
526 * In case of error the return value is an error pointer.
527 */
528 void *crypto_alloc_tfm(const char *alg_name,
529 const struct crypto_type *frontend, u32 type, u32 mask)
530 {
531 struct crypto_alg *(*lookup)(const char *name, u32 type, u32 mask);
532 void *tfm;
533 int err;
534
535 type &= frontend->maskclear;
536 mask &= frontend->maskclear;
537 type |= frontend->type;
538 mask |= frontend->maskset;
539
540 lookup = frontend->lookup ?: crypto_alg_mod_lookup;
541
542 for (;;) {
543 struct crypto_alg *alg;
544
545 alg = lookup(alg_name, type, mask);
546 if (IS_ERR(alg)) {
547 err = PTR_ERR(alg);
548 goto err;
549 }
550
551 tfm = crypto_create_tfm(alg, frontend);
552 if (!IS_ERR(tfm))
553 return tfm;
554
555 crypto_mod_put(alg);
556 err = PTR_ERR(tfm);
557
558 err:
559 if (err != -EAGAIN)
560 break;
561 if (signal_pending(current)) {
562 err = -EINTR;
563 break;
564 }
565 }
566
567 return ERR_PTR(err);
568 }
569 EXPORT_SYMBOL_GPL(crypto_alloc_tfm);
570
571 /*
572 * crypto_destroy_tfm - Free crypto transform
573 * @mem: Start of tfm slab
574 * @tfm: Transform to free
575 *
576 * This function frees up the transform and any associated resources,
577 * then drops the refcount on the associated algorithm.
578 */
579 void crypto_destroy_tfm(void *mem, struct crypto_tfm *tfm)
580 {
581 struct crypto_alg *alg;
582 int size;
583
584 if (unlikely(!mem))
585 return;
586
587 alg = tfm->__crt_alg;
588 size = ksize(mem);
589
590 if (!tfm->exit && alg->cra_exit)
591 alg->cra_exit(tfm);
592 crypto_exit_ops(tfm);
593 crypto_mod_put(alg);
594 memset(mem, 0, size);
595 kfree(mem);
596 }
597 EXPORT_SYMBOL_GPL(crypto_destroy_tfm);
598
599 int crypto_has_alg(const char *name, u32 type, u32 mask)
600 {
601 int ret = 0;
602 struct crypto_alg *alg = crypto_alg_mod_lookup(name, type, mask);
603
604 if (!IS_ERR(alg)) {
605 crypto_mod_put(alg);
606 ret = 1;
607 }
608
609 return ret;
610 }
611 EXPORT_SYMBOL_GPL(crypto_has_alg);
612
613 MODULE_DESCRIPTION("Cryptographic core API");
614 MODULE_LICENSE("GPL");
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